Molecular Biology Research will develop methods for molecular phenotyping of cancer cells by flow cytometry. Three specific aims are proposed: Aim one is to isolate cell populations of interest by cell sorting and determine gene amplification levels by PCR on less than 1000 cells (not the millions of cells required for standard blotting techniques). Aims two and three are to develop two new technologies, fluorescence in-situ hybridization on suspension (FISHES (aim 2) and fluorescence in-situ polymerase chain reaction (FLIP) (aim 3). The goal of these studies is to correlate gene expression at the mRNA level by FISHES or FLIP with protein expression by immunofluorescence.